On the evening of Jan. 4, the Bon Homme County Sheriff's Office started receiving calls about "possible poisonings," according to an arrest affidavit obtained by Fox News Digital.
"An investigation into the incident [led] me to believe that the patients were all under the influence of THC from a batch of brownies that were brought to the Community Center," a responding deputy wrote in the affidavit.
Bon Homme County Sheriff Mark Maggs went to Koranda's home the next day and spoke with the man's mother, who confirmed that she had taken her son's brownies to the card game.
The sheriff then went to the elementary school where Koranda teaches and asked him about the edibles.
Koranda reportedly told the sheriff that he had brought one pound of butter infused with THC, the main mind-altering ingredient in marijuana, back from Colorado.
"[Koranda] said he used half a pound of the THC butter to make the pan of brownies and then went to bed and his mother unknowingly took the brownies to the card game where several people ate them," the arrest affidavit says.
The Bon Homme County School District did not respond to a request for comment on Wednesday.
It's far from the first time that someone has mistaken regular sweets for marijuana-infused edibles.
A grandfather accidentally took a marijuana-laced cake to a group of nurses to say thank you.
A South Carolina elementary school teacher was arrested last year after one of her students picked a marijuana edible out of a reward box.